#app2{
    border: 1px solid black;
}
#app2 .tab-bar{
    display: flex;
    flex-wrap: wrap;
}
#app2 .tab-bar > li{
    border: 1px solid black;
    width: 50%;
    height: 30px;
}
#app2 .tab-bar > li.selected{
    color: white;
    background: gray;
}
#app2 .tab-content > li{
    border: 1px solid black;
    height: 40px;
    display: none;
}
#app2 .tab-content > li.active{
   display: flex;
   justify-content: center;
   align-items: center;
   color: red;
   
}